Field of the Invention
The present invention relates to the field of computer graphics and, in particular, to a system and method for computational highlight holography.
Description of the Related Art
A hologram creates a representation of a three-dimensional object viewable from the surface of a holographic substrate. A hologram should represent both binocular parallax and motion parallax. Binocular parallax gives rise to stereopsis, a perceived fusion of two slightly different images of a scene that are observed by a person's two eyes. Binocular parallax normally gives rise to a strong sensation of depth. Motion parallax refers to a different relative motion of objects at different depths in a scene perceived as a viewer moves with respect to the objects. Motion parallax also gives rise to a strong sensation of depth.
Traditional holography comprises an analog recording process whereby coherent light reflecting from a scene undergoes interference with a reference beam, and the resulting fringes are recorded on a photographic plate. In a reproduction step, for viewing the resulting hologram, light from the reference beam is diffracted by the fringes, recreating the original light field wavefront. The wavefront reproduces different views from which a viewer's eyes can observe the scene, thereby producing parallax effects that give rise to a sensation of depth. Traditional holograms are difficult to record, requiring sub-wavelength vibration control, and they can only be viewed using coherent light. Practical holography was enabled by white light transmission and reflection rainbow holograms. These holograms can include color and can be viewed using natural light. These properties are obtained by sacrificing parallax in the vertical direction. Rainbow holograms can be mass-produced using special embossing of micro-surface reliefs in plastic films. However, designing and recording white light holograms is still extremely expensive and not practical for producing large holograms.
A mechanical, or “scratch,” hologram is produced with a set of semicircular arcs scratched into a plastic or metal substrate. The arcs are conventionally scratched by hand in a manual process. Each arc corresponds to a point on an object being represented. Relative positions of the scratches correspond to relative positions of points on the object. A bright light is required to view a scratch hologram, which produces a set of highlight points corresponding to the points on the object. As the hologram substrate is moved with respect to a viewer, the highlight points move along their respective arc, approximating parallax and giving the user a sense of depth. Mechanical holograms typically offer little control over consistency, resolution or what is actually recorded and are labor intensive to produce.
As the foregoing illustrates what is needed in the art is an improved technique for fabricating a hologram.